Well-connected ZnO nanoparticle network fabricated by in-situ annealing of ZIF-8 for enhanced sensitivity in gas sensing application

[摘要] Low-power microheater platforms are promising in lowering power consumption during gas sensing processes. However, the small amount of activated-material and poor electrical contact greatly affect the sensitivity. Here, via in-situ annealing of a porous metal organic framework (MOF), ZIF-8, using a miniature heater electrode with a fast ramp rate (ca. 60 degrees C/s), we demonstrate the formation of a well-connected nanoparticle network with high porosity. Nanoparticle networks prepared in-situ exhibit significantly enhanced response to ethanol, defined as the ratio of sensor's resistance before and after gas exposure, compared to ex-situ annealed counterparts (>10 times larger response) and to commercially available nanoparticles (similar to 4 times larger response) at a sensing temperature of 250 degrees C. The mechanism of the enhanced performance is studied using AC impedance spectroscopy. The results indicate that the large number of highly accessible and effective adsorption sites on the in-situ annealed material are responsible for the enhancement.

[发布日期] 2021-10-01

[关键词] In-situ annealing;MOFs;Metal oxide nanoparticle network;Gas sensing;AC impedance spectroscopy